Physiological responses of coriander (Coriandrum sativum L.) to exogenous 2,4-epibrassinolide at different concentrations.

BACKGROUND: Brassinolide, known as the seventh plant hormone, can improve the photosynthetic capacity of plants, promote plant growth and development, promote the formation of horticultural crop yield, improve the quality of horticultural crops, and also improve the ability of plants to resist biological and abiotic stresses. RESULTS: The effects of different concentrations of exogenously sprayed 2,4-epibrassinolide (EBR) on growth, physiological and photosynthetic characteristics of 'All-round large leaf coriander' were studied in substrate culture. The results showed that 0.05, 0.1, and 0.5 mg.L- 1 EBR promoted the growth of coriander and increased the aboveground fresh and dry weights, with 0.5 mg.L- 1 EBR having the most significant effect. Spraying 0.1 mg.L- 1 EBR increased the content of soluble sugars and protein of coriander leaves. Spraying 0.1 and 0.5 mg.L- 1 EBR significantly increased the chlorophyll content and photosynthetic parameters of coriander leaves, and 0.5 mg.L- 1 EBR also significantly increased the chlorophyll fluorescence parameters of coriander leaves. Spraying 0.5 mg.L- 1 EBR upregulated the expression of CsRbcS, CsFBPase, and CsAld. Correlation analysis showed that aboveground fresh weight under exogenous EBR treatment was significantly positively correlated with aboveground dry weight, plant height, Pn, Gs, Ci, and CsAld (P < 0.05), and soluble sugar content was significantly positively correlated with the number of leaves, Y(II), qP, and CsRbcS. The results of the principal component analysis (PCA) showed that there was a significant separation between the treatment and the control groups. Spraying 0.5 mg.L- 1 EBR can promote the growth of coriander, improve the quality of coriander leaves, and strengthen coriander leaf photosynthetic capacity. This study provides new insights into the promotion of coriander growth and development following the application of exogenous EBR. CONCLUSION: Exogenous EBR treatment increased coriander plant height, leaf growth and aboveground dry weight, and enhanced photosynthesis. Exogenous spraying of 0.5 mg.L- 1 EBR had the most significant effect.

NOTA analogue: A first dithiocarbamate inhibitor of metallo-ß-lactamases.

The emergence of antibiotic drug (like carbapenem) resistance is being a global crisis. Among those resistance factors of the ß-lactam antibiotics, the metallo-ß-lactamases (MBLs) is one of the most important reasons. In this paper, a series of cyclic dithiocarbamate compounds were synthesized and their inhibition activities against MBLs were initially tested combined with meropenem (MEM) by in vitro antibacterial efficacy tests. Sodium 1,4,7-triazonane-1,4,7-tris(carboxylodithioate) (compound 5) was identified as the most active molecule to restore the activity of MEM. Further anti-bacterial effectiveness assessment, compound 5 restored the activity of MEM against Escherichia coli, Citrobacter freundii, Proteus mirabilis and Klebsiella pneumonia, which carried resistance genes of blaNDM-1. The compound 5 was non-hemolytic, even at a concentration of 1000 µg/mL. This compound was low toxic toward mammalian cells, which was confirmed by fluorescence microscopy image and the inhibition rate of HeLa cells. The Ki value of compounds 5 against NDM-1 MBL was 5.63 ±â€¯1.27 µM. Zinc ion sensitivity experiments showed that the inhibitory effect of compound 5 as a MBLs inhibitor was influenced by zinc ion. The results of the bactericidal kinetics displayed that compound 5 as an adjuvant assisted MEM to kill all bacteria. These data validated that this NOTA dithiocarbamate analogue is a good inhibitor of MBLs.

Response of soil microbial community diversity to continuous cucumber cropping in facilities along the Yellow River irrigation area.

Cucumber is an important cash crop; however, continuous cropping obstacles readily occur within the intensive production processes of facility horticulture. This study aimed to determine the effects of continuous cropping on soil quality and the microbial community in the rhizosphere soil of cucumbers. Rhizosphere soil of cucumber planted continuously for 4, 8, and 12 years was investigated, and soil that was not continuously planted was used as the control. Soil physicochemical properties, enzyme activity, microbial diversity, and richness were determined. The results showed that with the increase in continuous cropping years (0, 4, 8, and 12 years), soil total salt content continuously increased, while the pH value significantly decreased. Compared with the control, soil organic matter, alkali-hydrolyzed nitrogen, available phosphorus, available potassium, and nitrate nitrogen contents increased significantly after 4 and 8 years of continuous cropping. Spearman correlation analysis showed that pH was negatively correlated with sucrase or sucrose and available phosphorus was positively correlated with alkaline phosphatase. Compared with the control, the diversity and abundance of bacterial and fungal communities in cucumber rhizosphere soil decreased after 4 and 12 years of continuous cropping. Continuous cropping led to a significant increase in the richness of the dominant phylum of cucumber rhizosphere soil. Principal coordinates analysis showed that, compared with the control, the soil microbial community structure was significantly separated after 4, 8, and 12 years of continuous cropping, and the microbial community structure was most similar after 4 and 8 years of continuous cropping. In addition, redundancy analysis showed that pH was the main driver of soil microbial dominance. In conclusion, continuous cropping of cucumber along the Yellow River irrigation area has led to the deterioration of soil nutrients and microbial communities in that region. This experiment provides a theoretical foundation for addressing the challenges associated with continuous cropping in cucumber cultivation.

H2depda: An acyclic adjuvant potentiates meropenem activity in vitro against metallo-ß-lactamase-producing enterobacterales.

Metallo-ß-lactamase (MBL)-producing carbapenem-resistant Enterobacterales (CRE) pose an emerging threat to public health worldwide. An effective inhibitor of MBLs is therefore urgently needed for clinical use. In this study, two acyclic pyridine-containing ligands, H2dedpa and compound 8, were discovered with excellent activities when combined with meropenem (MEM) against MBL (blaNDM and blaIMP)-producing clinical isolates, including Escherichia coli, Citrobacter freundii, Proteus mirabilis, Enterobacter cloacae and Klebsiella pneumoniae. In particular, these two compounds improved the activity of MEM against E. coli harboring the blaNDM-4 gene by nearly 40,960 times. H2dedpa (IC50 = 0.17 ±â€¯0.04 µM) and compound 8 (IC50 = 0.04 ±â€¯0.02 µM) showed higher inhibitory activity against blaNDM-1 enzyme than the positive control ethylenediaminetetraacetic acid (EDTA, IC50 = 28.84 ±â€¯0.70 µM). A sterilization kinetics experiment showed that H2dedpain combined with MEM could kill 99.9% of bacteria within 24 h H2dedpa and compound 8 are therefore promising MBL inhibitors.